Avian Influenza
Revision as of 19:18, 13 October 2008 by Bepocock (talk | contribs) (New page: {{unfinished}} {{toplink |linkpage =Viruses |linktext =VIRUSES |sublink1=Orthomyxoviridae |subtext1=INFLUENZA |pagetype =Bugs }} <br> ===Subtypes=== *H1-15 and N1-9 have all been isolate...)
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Subtypes
- H1-15 and N1-9 have all been isolated
- Highly Pathogenic Avian Influenza (HPAI), caused by H5 and H7 isolates, is also known as Fowl Plague (FP) and is notifiable
- Chinese poultry are currently the main reservoir for H5N1, not wild birds
Pathogenesis
- HPAI is defined by:
- Heamorrhages
- Diarrhoea
- Sometimes nervous symptoms
- Sudden death
- H5 spread by feces and infected viscera (kidney/spleen are 100X more infectious than feces)
- H7 and other viruses are carried by 6% of the wild bird population and outbreaks mirror migrating patterns
- This poses significant risk to free-range flocks
Zoonotic potential
- A 2003 Dutch outbreak of a pathogenic H7 virus caused widespread conjunctivitis and flu-like symptoms with recovery among poultry workers
- Rural chinese children became infected with H5N1 via aerosol transmission, which was limited to upper respiratory symptoms and did not show horizontal spread
Control
- Prevention by proper hygiene and preventing contact with the wild bird population
- Isolation and cull of infected premises
- Firebreak cull in the case of uncontrolled spread
- Vaccination is not currently practiced for the following reasons:
- An eradication policy prevents it
- Vaccination favors the evolution of the virus, which might increase its virulence and drift